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  1. AnalogKid

    Morse buzzer

    If you use a USB connection for 5 V power and have arelatively high impedance speaker, like a 64 ohm headset driver, another option is an AC series CMOS hex inverter Schmitt trigger, the 74AC14. One inverter is the oscillator, and the other five drive both ends of the speaker in a BTL...
  2. AnalogKid

    Morse buzzer

    For simplicity, nothing can beat a piezo beeper. Battery, key, beeper. that's it. Most of them self-oscillate above 2 kHz for the most attention-getting sound with the least power. However, some larger ones have a lower freq that is less annoying. Still better than a buzzer. ak
  3. AnalogKid

    Cost-effective Production-Prototype Manufacturing

    Yes. No. Prototyping is expensive, and the more sophisticated the component packaging, the more expensive it is. If I could get a Lattice CPLD in a 40-pin DIP I'd be a happy guy. Were any test fixtures or x-ray inspection included in the prices? Aries and Ironwood(?) make TQFP-to-PTH...
  4. AnalogKid

    50Mhz Square wave generation.

    My guess is that he is by measuring the capacitor voltage after a fixed charge time (shunt mode). With a sine wave you could measure the capacitor impedance (series mode) in a half-bridge. Either way, changing soil moisture content might change the dielectric properties enough to affect the...
  5. AnalogKid

    50Mhz Square wave generation.

    Does it really require 50 MHz? Can you post a justification for this requirement? Please read post #1. If this is for a product, you just volunteered for a ton of certification and compliance testing. ak
  6. AnalogKid

    50Mhz Square wave generation.

    $0.90, single piece: https://www.digikey.com/product-detail/en/sitime/SIT2001BI-S2-33E-50.000000G/1473-1346-1-ND/5824455 ak
  7. AnalogKid

    Reversing Realy Switch?

    Impulse relays live in the industrial control world, often controlling motors. Hence, the contacts, and thus the coils, are fairly beefy. I don't know of any small, low power versions that aren't custom made for a specific OEM and application. A toggle flipflop circuit can turn any relay into...
  8. AnalogKid

    Laser Tag Gun - Short burst circuit

    Power source Voltage Available current Current needed by the load Physical size available Quantity A mechanical switch that makes contact for only a brief period of time when its button is pushed and held down is possible, but the E in EP stands for electronics. A circuit that takes a...
  9. AnalogKid

    Laser Tag Gun - Short burst circuit

    Lots of them. Do you have any information?" al
  10. AnalogKid

    Reversing Realy Switch?

    There is nothing in that datasheet that indicates that the relay is "alternate action" - energize once, 30 is connected to 87 and stays there after power is removed from the coil; energize again, 30 is connected to 87a and stays there after power is removed. It looks like a simple form-A (SPDT)...
  11. AnalogKid

    RC Low pass filter problems

    https://search.yahoo.com/search?n=10&ei=UTF-8&va_vt=any&vo_vt=any&ve_vt=any&vp_vt=any&vst=0&vf=all&vm=p&fl=0&p=crossover+network&vs= ak
  12. AnalogKid

    Lamp step control

    That is exactly the kind of trick I tried to describe, a very coarse PWM-to-power level control (simple on-off control in my case). I thought about putting everything into a 98-cent PIC, but I've got all of these parts... and the standard 4-foot fixtures. Better (and cheaper) to use them than...
  13. AnalogKid

    Lamp step control

    I have an idea, and the question is Does someone already make a product to do this? Garage ceiling light is bright enough for most things, but sometimes I'd like a lot more. I don't want to run a new line to a second wall switch, or have a pull string. And, I've got a basement full of parts...
  14. AnalogKid

    ISO a particular switch. Don't know what it's called/to look for

    Well, that changes everything. And it took only 15 posts. Since the water is there all the time and the pump does not have to run at the time the cat wants to drink, a programmable lamp timer can run the pump 5 or 10 minutes out of every hour to freshen the water. Available at Wal-Mart...
  15. AnalogKid

    ISO a particular switch. Don't know what it's called/to look for

    That's a start. Is it a line cord straight to the wall like an a table lamp, or is the plug a "wall wart" like a calculator power supply, or is there something between the wall and the pump, similar to but smaller than a laptop power supply? Since you will be switching the power to the pump...
  16. AnalogKid

    Variable Gain Amplifier

    Show us your work so far. ak
  17. AnalogKid

    ISO a particular switch. Don't know what it's called/to look for

    What powers the cat fountain? Is it a water tank with a pulp or valve, or is it a valve on a water supply line? What is the voltage rating or the valve or pump? Not all switches work with all devices, so it is important to know what is being switched. ak
  18. AnalogKid

    Amplifier circuit using common parts

    What signal? source voltage source frequency range source impedance amplifier gain amplifier output power amplifier output voltage amplifier output impedance load ak
  19. AnalogKid

    Need to light different LEDs when polarity is reversed

    Standard small red and green LEDs average around 2 V forward voltage drop. A 1 K resistor will deliver 10 mA. 470 ohms will deliver 21 mA, a safe max value. ak
  20. AnalogKid

    Need to light different LEDs when polarity is reversed

    What is the voltage across the motor?
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